Basin Research - Volume 33, Issue 2, 2021

There remains a limited understanding of the controls of pre‐existing structures on the architecture of deep‐water progradational sequences. In the Northern Taranaki Basin (NTB), New Zealand, Pliocene post‐extensional sedimentary sequences overlie Miocene back‐arc volcaniclastic units. We utilize seismic reflection datasets to investigate the relationships between the buried back‐arc mound‐shaped structures, and the spatio‐temporal changes in clinoform architecture and the associated progradational system elements within the overlying continental slope margin sequences. Our results reveal the following: (a) buried mound‐shaped structures in the northern domain of the study area, overlain by younging progression of shelf‐to‐basin prograding clinoforms; (b) folding of the deeper clinoforms that systematically decrease in magnitude with shallowing depth from the top of the seamounts; (c) overall, the N‐S‐trending continental slope margin evolves from a highly curvilinear/angular trend in the deeper clinoforms (Units 1 and 2) into a rectilinear geometry within the shallower post‐extensional intervals (Unit 3 and shallower); (d) Units 1 and 2 characterized by dominance of stacked offlap breaks and over‐steepened (7–10°) clinoform foreset slopes in the northern domain, and dominance of gently dipping foreset slopes (<6°) in the south; (e) Unit 3 shows very low (<5°) and intermediate (5–7°) foreset slopes across the entire survey; (f) in the northern domain, differential loading by prograding sequences about the buried seamounts and horst–graben structures induced a differential compaction of the deeper units, which influenced a temporal pinning of the prograding slope margin in pre‐Unit 2 times and (g) wide, closely spaced channel incision into over‐steepened slopes dominate the deeper prograding sequence in the northern domain, whereas narrower, straighter channels dominate the south. We show that the buried pre‐existing structures constitute rigid buttresses that modulated the syn‐depositional topography and post‐depositional architecture of the prograding sequences in the NTB. Our findings present a distinction in the controls on progradational sedimentation patterns between magmatic and non‐magmatic continental margins.

Conceptual block diagrams showing our proposed tectono‐sedimentary evolution of the western Sivas Basin (red box in inset map) during deposition of TS‐1 (a,b,c) and TS‐2 (d); see Figure 2 for location of X‐X′. (a) Maastrichtian to Paleocene Tauride‐Pontide collision in the easternmost Sivas Basin led to incomplete subduction and a remannt ocean setting in the western Sivas Basin; additional accommodation space may have been generated by an enigmatic phase of extension. (b) Middle Eocene contraction in the Tauride thrust belt to the south led to rapid subsidence in the Sivas Basin and a transition to a flexural foreland basin setting. (c) Northward propagation of shortening during the latest Eocene marked another switch to a fragmented foreland setting involving basin inversion, uplift and isolation from the marine realm, and initiation of the southern Sivas fold‐thrust belt (SSFTB), which structurally partitioned the Sivas Basin into a southern wedge‐top and northern evaporitic foreland basin during the Oligocene (d). A – Altınyayla; B – Bünyan; other abbreviations as in Figure 1.

The Sivas Basin overlaps the northern Neotethys suture zone in central Anatolia (Turkey) and contains a ca. 12‐km thick succession of Cenozoic strata that provides an exceptional record of major tectonic transitions from subduction to continental assembly and tectonic escape. Consensus regarding the tectonic and palaeogeographic evolution of this segment of the Arabia‐Eurasia collision zone has been hindered by uncertainty in the tectonic setting of the early (Palaeogene) Sivas Basin, which has been variably interpreted as a remnant ocean, forearc, foreland, wedge‐top or intracontinental extensional basin. Here we integrate new geologic mapping (>5,000 km²), stratigraphy, facies analysis and U‐Pb geochronology from the western Sivas Basin to produce a detailed time‐stratigraphic framework and a refined Palaeogene tectono‐sedimentary model for the Sivas Basin. Earliest marine sedimentation occurred during the Maastrichtian‐Palaeocene in a remnant ocean setting due to incomplete closure of the northern Neotethys Ocean. Rapid accumulation of >2 km of basin floor turbidites during the middle to late Eocene reflect a transition to a foreland setting. A major late Eocene unconformity (ca. 38–34 Ma) coincides with the initiation of the north‐vergent southern Sivas fold‐thrust belt, which inverted and structurally partitioned the basin into a southern wedge‐top and a northern evaporitic foreland basin; the entire basin was dominantly nonmarine after this unconformity. Published palaeomagnetic data integrated with a newly discovered tuff dated at 31.9 Ma reveal that the 2.8‐km thick Altinyayla Formation was deposited from ca. 34 to 26 Ma in an unconfined braided fluvial system. Close stratigraphic correlations between the western, central and northern Sivas Basin suggest that the entire basin evolved from a remnant ocean to peripheral retro‐foreland basin during the middle to late Eocene, and finally a fragmented foreland basin since the Oligocene. This general evolution may be a characteristic of such sedimentary basins formed on suture zones across Anatolia and in other collisional orogens globally.

The Greater Caucasus orogen on the southern margin of Eurasia is hypothesized to be a young collisional system and may present an opportunity to probe the structural, sedimentary and geodynamic effects of continental collision. We present detrital zircon U‐Pb age data from the Caucasus region that constrain changes in sediment routing and source exposure during the late Cenozoic convergence and collision between the Greater Caucasus orogen and the Lesser Caucasus, an arc terrane on the lower plate of the system. During Oligocene to Middle Miocene time, following the initiation of deformation within the Greater Caucasus, marine sandstones and shales were deposited between the Greater and Lesser Caucasus, and detrital zircon age data suggest no mixing of Greater Caucasus and Lesser Caucasus detritus. During Middle to Late Miocene time, Greater Caucasus detritus was deposited onto the Lesser Caucasus basin margin, and terrestrial, largely conglomeratic, sedimentation began between the Greater and Lesser Caucasus. Around 5.3 Ma, upper plate exhumation rates increased and shortening migrated to pro‐ and retro‐wedge fold‐thrust belts, coinciding with the initiation of foreland basin erosion. Sediment composition, provenance and structural data from the orogen together suggest the existence of a wide (230–280 km) marine basin that was progressively closed during Oligocene to Late Miocene time, probably by subduction/lithospheric underthrusting beneath the Greater Caucasus, followed by initiation of collision between the Lesser Caucasus arc terrane and the Greater Caucasus in Late Miocene to Pliocene time. The pace of the transition from hypothesized subduction to collision in the Caucasus is consistent with predictions from numerical modeling for a system with moderate convergence rates (<13 mm/yr) and hot lower plate continental lithosphere. Basement crystallization histories implied by our detrital zircon age data suggest the presence of two pre‐Jurassic sutures between stable Eurasia and the Lesser Caucasus, which likely guided later deformation.

The Greater Caucasus may constitute a natural example of early continental collision. New detrital zircon U‐Pb geochronology data, together with published Cenozoic stratigraphy and structural data from the Greater Caucasus, suggests collision began in the Late Miocene to Pliocene, leading to diachronous changes in deformation and sedimentation in the orogen and associated basins.

Subsidence and growth rates of the Triassic units compared to subsidence mechanisms based on Schlager (1981). The accumulation rate of stratigraphic units is displayed in comparison to the derived total subsidence curve. Two kinds of units can be individuated based on their total subsidence curves: one group for which accommodation space was driven by thermal subsidence, and a second group falling above the thermal subsidence curve, indicating subsidence rates requiring salt expulsion in addition to cooling.

Subsidence analysis study for several Triassic carbonate platforms from the eastern Northern Calcareous Alps shows that salt expulsion allowed for the growth of thick isolated depocentres (>1.5 km) at rates faster than those tectonic subsidence alone can provide. Our results, in addition to independent regional geological evidence, argue against previous models of thick‐skinned extension controlling accommodation space. Differential sedimentary loading and stretching of the salt layer can explain the development of the Triassic isolated carbonate platforms in the Northern Calcareous Alps, with salt expulsion being proportional to the growth potential of the carbonate producers. Aside of topographic loads, early diageneses of carbonates allow for the density inversion between sediment and salt, with differential loading by carbonate aggradation leading to a self‐sustained feedback cycle of density‐driven and gradient load subsidence; stretching of the salt layer and extensional deformation of its overburden, as constrained by cross‐section restoration, also contributed to diapir initiation and salt expulsion. Our model can: (a) explain the occurrence of isolated Middle Triassic carbonate platforms in the eastern Northern Calcareous Alps, and (b) differentiate between accommodation space controlled by (local) salt expulsion and by (regional) tectonic subsidence. The Triassic Neo‐Tethys shelf of the studied area constituted therefore a salt wall and minibasin province. This contribution and methods herein can also be applied to other carbonate platform systems developed on salt basins, especially where the transition from rift to drift remains unclear.

This study suggests that strike variation in shelf‐margin erosional and depositional processes were caused principally by the locations and timings of tectonic deformation.

Extensive 2D multichannel seismic (~17340 km) and well data provide an opportunity to investigate the source to sink processes and triggering factors of the Late Miocene sedimentary record in the Ulleung Basin, East Sea (Sea of Japan). The sedimentary succession of the basin comprises two distinct deep‐water depositional systems, which are characterised by stacked mass‐transport deposits (MTDs) and subsequent submarine fan. Individual MTDs spread downslope over areas as large as ~9000 km² with NW–SE or N–S flow direction. The deep‐water fan consists of distributary channel‐lobe complexes (DLCs) that are 80 km wide and 140 km long. Two major tectonic periods driven by structural deformation characterised the Late Miocene deep‐water sedimentation growth. During early to middle Late Miocene (10.3–8.2 Ma), the MTDs were sourced from degraded fold triggered by slope oversteepening and seismicity on the southeastern basin margin, where the thrust‐and‐fold belt developed. In the middle to latest Late Miocene (8.2–6.3 Ma), the DLCs were fed by canyon‐channel systems on the southwestern basin margin, where the tectonic uplift of the anticline was active. Therefore, this study suggests that strike variation in shelf‐margin erosional and depositional processes were caused principally by the locations and timings of tectonic deformation.

Cr‐spinel from the Snadd and De Geerdalen formations are distinctly different from Cr‐spinel of the same depositional age to the east of the Uralian Orogen. Major element compositions of detrital Cr‐spinel in the Carnian Osipai Fm. north Siberia is consistent with Cr‐spinel from a large igneous province, while Snadd and De Geerdalen formation Cr‐spinel indicate a ophiolitic source. The addition of trace element compositional data of the Snadd and De Geerdalen formation Cr‐spinel, help identify a metamorphic alteration history of the detrital grains.

Investigations of sandstone provenance often involve U–Pb dating and chemical/mineralogical investigations of detrital minerals that are stable in sediments. As most stable detrital minerals are from felsic–intermediate rocks, investigations of the only mafic–ultramafic mineral considered stable in sediments, chromian spinel (Cr‐spinel), can reveal contributions from mafic–ultramafic sources. Cr‐spinel chemical compositions are tied to petrogenesis, making it possible to identify the nature of, and differentiate between, potential sources. Earlier detrital Cr‐spinel studies have focused on major and minor element compositions, however, the advent of laser‐ablation analytical techniques now allow routine mineral trace element analyses. Here, we integrate major, minor and trace element compositions of detrital Cr‐spinel from sandstones with a well‐characterised provenance from the Triassic (Anisian to Early Norian) Snadd and De Geerdalen formations of the Barents Shelf. The analysed Cr‐spinel compositions are depleted in the major element cations Fe³⁺, Al and Mg and enriched in Cr and Fe²⁺. Relative to MORB chromite, the minor and trace element data show high concentrations of Zn, Co and Mn, low concentrations of Ni and Ga and variable concentrations of Ti, V and Sc. The major element compositions of the detrital Cr‐spinel are similar to ophiolite‐associated Cr‐spinel, while the trace element compositions indicate a more complex petrogenesis influenced by metamorphic alteration. The compositional variations between sample locations are small, suggesting similar source rocks for the detrital Cr‐spinel throughout the study area. The most likely sources of the Cr‐spinel grains are metamorphosed ophiolite complexes in the Uralian Orogen, in accordance with earlier provenance studies. The novel addition of trace element compositions to detrital Cr‐spinel studies adds significant source‐sensitive information.

Palaeobathymetric variations and organic matter dilution controlling TOC trends. (a) Tectonically stable areas or areas affected by minor faulting. (b) Area affected by active normal faults.

Syn‐rift successions contain both prolific organic‐rich and coarse‐grained rocks, but these rocks are usually studied independently. Thus, the interplay among organic matter deposition, tectonics and sediment supply is not commonly assessed. In this study, we use well logs, Total Organic Carbon (TOC) content, biostratigraphy and seismic data from the SW Barents Sea to unravel the variability of organic‐rich successions and its interaction with potential reservoir rocks in areas affected by active normal faulting versus tectonically stable areas. Four Transgressive‐Regressive (T‐R) sequences were defined for the Middle to Upper Jurassic Fuglen Formation and for the organic‐rich Upper Jurassic to lowermost Cretaceous Hekkingen Formation. Three TOC trends, controlled by palaeobathymetric variations, and organic matter dilution, were identified within the two main organic‐rich sequences (sequences 2 and 3): (a) wells with the highest TOC values (>10 wt %) at the base of the succession; (b) wells with the highest TOC values at the top of the succession and (c) wells with high TOC values at the base and top of the succession. Our interpretation indicates that fault activity controlled the TOC trends in two different ways: Firstly, by creating a sharp topographic contrast‐triggering hyperpycnal flows, and shallowing the footwalls, where higher oxygen content and less developed stratified waters lowered organic matter preservation. Secondly, by significantly increasing the input of clastic material, which inherently led to dilution of organic matter and resulted in lower TOC values (<6 wt %). We interpret that sand deposition was controlled by the size and geomorphology of the sediment source areas. The western part of the study area (i.e. the Loppa High) was characterized by uplifted footwall islands and localized sands along their flanks, whereas the southern part (i.e. the Finnmark Platform) constituted a larger sediment source area for the Volgian age. This work has implications for a better understanding of the distribution of reservoir and source rocks in active rift basins.

Base‐of‐scarp deposits represent unsteady‐state systems showing primary inclined bedding and aggradational to progradational geometries along active fault scarps. The progressive angle decrease recognised in the younger strata promotes the architectural change of the system to either shola‐water or Gilbert‐type systems.

The term base‐of‐scarp is proposed for those submarine deposits controlled by a fault and physically disconnected from their more proximal counterpart located on the footwall, although genetically linked to it. These systems differ from conventional fault‐controlled deltas, such as shoal‐ and Gilbert‐type, because they are entirely subaqueous and lack equilibrium morphology—a steady state in which the system grows in size without altering its shape. We present field examples of fault‐controlled deposits from the Crati Basin and the Messina Strait (southern Italy) consisting of stratigraphic clastic wedges that thin towards and onlap onto the active margin with primary inclined bedding. Beds are composed of immature coarse‐grained gravels and sand, lack structures representative of wave‐action and reflect gravity‐driven processes such as debris flow, debris fall and high‐density turbidity currents. These deposits represent the unsteady‐state phase in which the system grows reducing its slope angle leading to conditions under which the unsteady state may eventually turn into a Gilbert‐type or shoal‐water system. A diagram for fault‐controlled base‐of‐scarp (B), Gilbert (G) and shoal‐water (S) deposits is presented, including their steady‐ and unsteady states, and the conceptual conditions under which a base‐of‐scarp system might evolve into Gilbert‐type or shoal‐water systems and vice versa.

Understanding the evolution of submarine channel‐lobe systems on salt‐influenced slopes is challenging as these systems react to subtle, syn‐depositional changes in sea‐floor topography. The impact of large blocking structures on individual deep‐water systems is well documented, but our understanding of the spatial and temporal evolution of extensive channel‐lobe systems on slopes influenced by relatively modest salt structures is relatively poor. We focus on Late Miocene deep‐water depositional systems contained within a c. 450 ms TWTT thick interval imaged in 3D seismic reflection data from the contractional salt‐tectonic domain, offshore Angola. Advanced seismic attribute mapping, tied to seismic facies analysis and time‐thickness variations, reveal a wide range of interactions between structurally induced changes in slope relief, deep‐water sediment routing, geomorphology and sedimentology. Five seismic units record a striking tectono‐stratigraphic within eight minibasins. We observe gradual channel diversion through lateral migration during times of relatively high structural growth rate, as opposed to abrupt channel movement via avulsion nodes during times of relatively high sediment accumulation rate. Our models capture the response of deep‐water depositional systems to the initiation, maturation, and decay of contractional structures on salt‐influenced slopes. The initiation stage is defined by small, segmented folds with deep‐water depositional system being largely able to transverse multiple minibasins. In contrast, the maturity stage is characterised by large, now‐linked high‐relief structures bounding prominent minibasins leading to ponding and large‐scale diversion of channel‐lobe systems and the emplacement of MTCs derived from nearby highs. The decay stage is expressed by structures that are shorter and more subdued than those characterising the maturity stage; this leads to a more complicated array of channel‐lobe system, the evolution of which is still influenced by bypass, diversion and ponding. During the decay stage, remnant structures still exert a subtle but key control on the development and positioning of avulsion nodes.

Conventional three‐dimensional (3D) seismic data reveal abundant igneous activity on the Modgunn Arch, mid‐Norwegian margin. Magmatic sills and associated hydrothermal vent complexes located at various depths prove the repeated utilisation of Paleocene‐Eocene magmatic conduits. In total, 125 sills and 85 hydrothermal vent complexes were identified and mapped, with vent complexes ranging in diameter from 300 to 3,100 m and sills from 0.5 to 50 km. Three examples of stacked vent complexes are presented, revealing large eruptions of hydrothermal fluids vertically through the same conduit, from sills to the palaeo‐sea floor. The vent complexes are found throughout Paleocene strata (66–56 Ma), whilst at least ten (10) vents were active during the Eocene. This study emphasises the importance of characterising ancient magmatic structures, as hydrothermal conduits and vent structures were, and may still be, reutilised as preferential fluid flow pathways to shallower strata. A minimum of four phases of hydrothermal vent complex formation are inferred. Cretaceous faults are both bypassed and used for magma and fluid flow. The reutilisation of magmatic structures here described may bring to light previously overlooked plays and renew interest in exploring magma‐rich continental margins.

Amplitude anomalies and stacked hydrothermal vent complexes (HTVCs) indicate reutilisation of HTVCs for fluid flow. (a) High‐amplitude anomaly shown in plan view, located above a hydrothermal vent complex (HTVC), indicating possible gas and fluid flow across the HTVC. (b) Seismic section showing an HTVC with the high‐amplitude anomaly identified and mapped in (a). (c) Seismic section with two stacked HTVCs and seismic dimming in between, indicating two episodes of hydrothermal venting. Bright amplitudes above suggest subsequent fluid flow across the HTVCs.

Interactions between footwall‐, hangingwall‐ and axial‐derived depositional systems make syn‐rift stratigraphic architecture difficult to predict, and preservation of net‐erosional source landscapes is limited. Distinguishing between deposits derived from fault‐scarp degradation (consequent systems) and those derived from long‐lived catchments beyond the fault block crest (antecedent systems) is also challenging, but important for hydrocarbon reservoir prospecting. We undertake geometric and volumetric analysis of a fault‐scarp degradation complex and adjacent hangingwall‐fill associated with the Thebe‐2 fault block on the Exmouth Plateau, NW Shelf, offshore Australia, using high resolution 3D seismic data. Vertical and headward erosion of the complex and fault throw are measured. Seismic‐stratigraphic and seismic facies mapping allow us to constrain the spatial and architectural variability of depositional systems in the hangingwall. Footwall‐derived systems interacted with hangingwall‐ and axial‐derived systems, through diversion around topography, interfingering or successive onlap. We calculate the volume of footwall‐sourced hangingwall fans (VHW) for nine quadrants along the fault block, and compare this to the volume of material eroded from the immediately up‐dip fault‐scarp (VFW). This analysis highlights areas of sediment bypass (VFW > VHW) and areas fed by sediment sources beyond the degraded fault scarp (VHW > VFW). Exposure of the border fault footwall and adjacent fault terraces produced small catchments located beyond the fault block crest that fed the hangingwall basin. One source persisted throughout the main syn‐rift episode, and its location coincided with: (a) an intra‐basin topographic high; (b) a local fault throw minimum; (c) increased vertical and headward erosion within the fault‐scarp degradation complex; and (d) sustained clinoform development in the immediate hangingwall. Our novel quantitative volumetric approach to identify through‐going sediment input points could be applied to other rift basin‐fills. We highlight implications for hydrocarbon exploration and emphasize the need to incorporate interaction of multiple sediment sources and their resultant architecture in tectono‐stratigraphic models for rift basins.

An integrated approach developed to assess the relationship between footwall degradation and hangingwall deposition from an individual subsurface fault block that disentangles syn‐rift basin architecture through quantification of different sediment sources, which can be applied to other rift basins

The structural depression that occupies the Okavango Basin in southern Africa comprises a depo‐centre within the intracratonic Kalahari Basin where sediments of the Cenozoic Kalahari Group have accumulated. The Okavango Basin has been formed due to stretching and subsidence at an area of diffused deformation, southwestwards to the main East African Rift System (EARS). Sediments from two full Kalahari Group sequences, located on opposite sides of the Gumare Fault that forms a major fault within the Okavango Basin, were studied to determine their provenance and chronology. Terrestrial Cosmogenic Nuclide (TCN) ²⁶Al/¹⁰Be burial dating was used to constrain a chronostratigraphical framework, and Pb, Sr, and Nd isotopic ratios combined with geochemical and sedimentological analyses were applied to track the source areas of the sediments.Results indicate the following sequence of basin filling: (a) Accumulation between ca. 4–3 Ma during which the currently downthrown (southern) block received a mixture of sediments mostly from the Choma‐Kalomo, Ghanzi‐Chobe, and Damara terranes, and possibly from the Lufilian Belt and/or Karoo basalts during earlier stages of deposition. Simultaneously, the upthrown (northern) block received sediments from more distant Archean sources in the Zimbabwe and/or Kasai cratons, (b) Hiatus in sedimentation occurred at both sites between ca. 3–2 Ma, (c) Sediments on both sides of the Gumare Fault share a similar source (Angolan Shield) with minor distinct contributions to the downthrown block from the Kasai Craton and local sources input to the upthrown block, and (d) Regional distribution of aeolian sand since at least 1 Ma. The change in source areas is attributed to rearrangements of the drainage systems that were probably linked to vertical crustal movements on the margins of the Okavango Basin. The tectonically induced morphodynamics controlled the landscape evolution of the endorheic basin where vast lakes, wetlands and salt pans have developed through time.

Capture areas of the western Okavango Basin during the Pliocene (a) and the early Pleistocene (b). The change in provenance that occured around the Pliocene‐Pleistocene transition is attributed to adjustments of the drainage systems to axial crustal uplift, resulting in the formation of large waterbodies.

Schematic overview of the distribution and extent of Paleogene proto‐ranges (dark grey) and their present‐day pendants (light grey) in the Central Andes of NW Argentina and surrounding regions. Black and white arrows indicate the vergence of faults with Eocene activity. Documented Paleogene tectono‐sedimentary features (white dots) and Paleogene thermochronological ages (black dots) are shown. Black line shows the western limit of Cretaceous rift activity. Light‐orange filling area indicates the zone in which penetrative Paleozoic deformation dies out towards the east (Mon & Hongn, 1987). The western and eastern borders of this zone contain Lower Paleozoic sequences respectively with intense (west) and little or no (east) Paleozoic deformation.

The structural and topographic evolution of orogenic plateaus is an important research topic because of its impact on atmospheric circulation patterns, the amount and distribution of rainfall, and resulting changes in surface processes. The Puna region in the north‐western Argentina (between 13°S and 27°S) is part of the Andean Plateau, which is the world's second largest orogenic plateau. In order to investigate the deformational events responsible for the initial growth of this part of the Andean plateau, we carried out structural and stratigraphic investigations within the present‐day transition zone between the northern Puna and the adjacent Eastern Cordillera to the east. This transition zone is characterized by ubiquitous exposures of continental middle Eocene redbeds of the Casa Grande Formation. Our structural mapping, together with a sedimentological analysis of these units and their relationships with the adjacent mountain ranges, has revealed growth structures and unconformities that are indicative of syntectonic deposition. These findings support the notion that tectonic shortening in this part of the Central Andes was already active during the middle Paleogene, and that early Cenozoic deformation in the region that now constitutes the Puna occurred in a spatially irregular manner. The patterns of Paleogene deformation and uplift along the eastern margin of the present‐day plateau correspond to an approximately north‐south oriented swath of reactivated basement heterogeneities (i.e. zones of mechanical weakness) stemming from regional Paleozoic mountain building that may have led to local concentration of deformation belts.

To better constrain late Neogene denudation of the Himalayas, we analysed in situ ¹⁰Be concentrations in 17 Neogene sediment samples of the Surai section (central Nepal) and two modern sediment samples of the Rapti River. We first refined the depositional ages of the Surai section from 36 new paleomagnetic analyses, five ²⁶Al/¹⁰Be burial ages, and, based on the Dynamic Time Warping algorithm, 10⁴ automatically calculated likely magnetostratigraphic correlations. We also traced changing sediment sources using major element and Sr‐Nd isotopic data, finding at 4–3 Ma a switch from a large, trans‐Himalayan river to a river draining only the Lesser Himalaya and Siwalik piedmont, increasing the contribution of recycled sediments at that time. ¹⁰Be concentrations in Neogene sediments range from (1.00 ± 0.36) to (5.22 ± 0.98) × 10³ at g^–1 and decrease with stratigraphic age. Based on a flood plain transport model, our refined age model, and assuming a drainage change at 4–3 Ma, we reconstructed ¹⁰Be concentrations at the time of deposition. Assuming cosmogenic production rates similar to those of the modern basins, we calculated palaeodenudation rates of 0.9 ± 0.5 to 3.9 ± 2.7 mm a^–1 from ca. 6 to 3 Ma in the palaeo‐Karnali basin and 0.6 ± 0.2 to 1.6 ± 0.8 mm a^–1 since ca. 3 Ma in the palaeo‐Rapti basin. Given the uncertainties and similar modern values of ~2 mm a^–1, the palaeo‐Karnali denudation rates may have been steady at ~1.7 ± 0.3 mm a^–1 for the last ca. 6 Ma. A transient acceleration of the denudation in the palaeo‐Rapti basin of ~1.5 mm a^–1 since ca. 1.5 Ma was likely due to the reworking of older, ¹⁰Be‐depleted Siwalik sediments in the foreland. If true, this steadiness of the denudation rates may suggest that Quaternary glaciations did not largely affect Himalayan denudation.

Temporal evolution of reconstructed 10Be palaeoconcentrations and derived palaeodenudation rates in the Surai Khola. Palaeoconcentrations (left) are corrected for radioactive decay and exposure in the floodplain (see text). Denudation rates were calculated assuming that the sediments of the Surai section were deposited by a Karnali‐type trans‐Himalayan river prior to ca. 3.5 Ma (middle), and by a Rapti‐type midland‐draining river since ca. 3.5 Ma (right).

The evolution of southern Gulf of Mexico deep‐marine depositional systems was strongly controlled by onshore dynamic and transpressional tectonics through the Neogene and into the modern. Nearshore extensional accommodation generated by margin collapse and salt inflation served to progressively starve the deep southern Gulf of sediment. This is recorded in the deep‐water basin center as a transition from large Miocene submarine channel systems to late Miocene to modern mass transport deposits and supercritical sediment waves.

Newly available two‐dimensional (2D) and limited three‐dimensional (3D) reflection seismic data coupled with publicly available well and core data were used to generate the first comprehensive regional basin evolution model for the deep‐water Neogene to recent southern Gulf of Mexico (GoM). This evolution is presented in the context of contemporaneous onshore tectonic drivers and predecessor basin tectonic history. Dynamic uplift to the west in North America, transpression to the south and tectonically influenced salt tectonics to the east served to collapse the margins of the southern Gulf of Mexico Basin throughout the late Neogene and into the modern. This collapse and salt inflation served to shut off efficient sediment transport into the axial deep basin. Newly developed nearshore extensional accommodation along both the western margin of the basin and salt‐rooted orogenic structures to the south and east appear to have baffled coarser‐caliber sediment input from southern (Mexican) sediment sources into the deep Gulf of Mexico Basin beginning in the late Miocene. This sequence is recorded in the southern GoM basin by a transition from large early–mid Miocene submarine channel belts to late Miocene–recent sediment wave fields and mass transport deposits. Improved resolution of new 2D and 3D subsurface seismic reflection data shows that sediment waves of the southern Gulf of Mexico are supercritical bedforms, long wavelength antidunes and cyclic steps, not contourites. These supercritical bedforms are among the most spatially expansive and morphologically largest documented globally. The location and evolution of these bedforms appears closely tied to the tectonically driven history of margin collapse, salt inflation and the starving of the deep basin of coarse‐grained sediment. Cumulatively, the tectonic drivers that intuitively should have increased sediment flux into the deep southern Gulf of Mexico acted to ‘pinch off’ the basin, starving it of sediment supplied from southern sediment sources.

Reconstructing the original depositional level of the Mesozoic and older c‘salt giants’ can reveal if their basins became filled to global sea level, but is complicated by dissolution, diapirism and because the time elapsed is so great. This is less of a problem in the Red Sea, a young rift basin that is transitioning to an ocean basin and where the evaporites away from coastal fringes are less affected by diapirism. In this study, we explore vertical movements of the evaporite surface of the central Red Sea imaged with deep seismic profiling, for the period of time after most evaporite deposition ended at 5.3 Ma (the Miocene‐Pliocene boundary). This boundary is readily mapped across the basin as a prominent reflection in seismic data correlated with stratigraphy at three DSDP sites. We quantify changes in the average elevation of the evaporite surface due to (a) thermal lithospheric subsidence, (b) isostatic loading by Plio‐Pleistocene sediments and water, (c) deflation needed to balance the volume of evaporites overflowing oceanic crust of 5.3 Ma age, (d) loss of halite by dissolution and (e) dynamic topography. Our best estimate of the evaporite level (−132 m air‐loaded or −192 m water‐loaded) lies below the range of estimated global sea level towards the end of the Miocene, suggesting that the basin remained under‐filled. If geological interpretations of shallow water conditions existing at the end of the Miocene (Zeit Formation) are correct, this implies that the water level of the Red Sea declined and was unstable. These calculations illustrate how spreading of evaporites can enhance thermal subsidence to cause rapid development of accommodation space above major evaporite bodies, which in the Red Sea case has remained largely unfilled.

A series of five corrections are made to the present level of the Miocene evaporites in the central Red Seat, suggesting that the basin remained under‐filled at the Miocene‐Pliocene boundary (i, ii).

This study investigates overpressure evolution and its relationship to the spatial and temporal changes in the sedimentation rate in the passive continental margin of offshore Suriname. We analysed well data to estimate pore pressure at the well locations and to interpret relevant overpressure‐generating mechanisms. Three‐dimensional basin modelling was performed to reconstruct overpressure evolution in the area. The well data indicated disequilibrium compaction as the main overpressure‐forming mechanism. The results of the modelling indicated a temporal variation in the sedimentation rate caused cycles of overpressure formation in the region. Periods of high sedimentation lead to overpressure formation, and this overpressure dissipates during periods of quiescent sedimentation. The latest overpressure development since the Middle–Late Miocene was triggered by a notable increase in the siliciclastic supply to the basin, which reflects the Andean uplift and reorganization of the drainage system. Spatial changes in the sedimentation rate resulted in a lateral variation in the amount of overpressure. Disequilibrium compaction generated large overpressure in the area with a high‐sedimentation rate because of the fast increasing rate of overburden load. In addition, the high‐temperature condition beneath the rapid sedimentation area could cause additional mechanisms for overpressure formation in the deeper part of the basin. This study reveals that the complex overpressure history and its lateral variation in offshore Suriname were mainly caused by a single controlling factor (i.e. the sedimentation rate). This article gives an insight into overpressure evolution in sedimentary basins by considering the perspective of the spatio‐temporal variation in the sedimentation rate and its connection with hinterland evolution.

Schematic diagram showing the relationship between spatio‐temporal changes in the sedimentation rate and overpressure evolution in offshore Suriname.

The glacimarine shelf‐edge is a complex depositional environment in which the interplay between accommodation and glaciation has played an important role in influencing sediment deposition and margin architecture. It can be challenging to unravel the history of basin infill in these areas, particularly where landforms are deeply buried. This study presents an integrated workflow for deciphering the architecture and evolution of erosional and depositional elements in a crucial location of the south‐western Barents Sea margin, with a focus on the comparatively poorly understood processes and patterns of glacimarine sedimentation that occurred during the Pliocene and Early Pleistocene. Wellbore interpretations of lithology are combined with the analysis of seismic facies, geomorphology and attributes using merged 3D seismic reflection data to investigate the morphology and development of buried landforms and depositional features on the outer‐shelf, shelf edge and upper‐slope. The Pliocene (preglacial) slope system is dominated by upper‐slope channels, upper‐slope channels with associated sediment lobes, and mass‐transport deposits. The first appearance of mega‐scale glacial lineations in the study area is close to the onset of the Pleistocene (around 2.58 Ma), suggesting that an ice stream reached the palaeo‐shelf edge during the earliest Pleistocene. The prevalence of upper‐slope channels and mass‐transport deposits throughout the Pleistocene stratigraphy shows that the basinwards transfer of sediment took place mainly by evacuation of sediment through relatively linear channels combined with mass‐movement events. The results presented in this study have implications for understanding the glacial history of the south‐western Barents Sea and sedimentary processes on glacimarine shelf edges more generally.

3D spatial and temporal depositional model of the study area

Continental passive margins and their hinterlands in the Atlantic realm have been the locus of many Low Temperature Thermochronology (LTT) and time‐Temperature (t‐T) modelling studies that evidence pre‐, syn‐ and post‐rift episodic km‐scale exhumation and burial episodes. In this study, we integrate data from over 30 published LTT and t‐T modelling studies from Morocco and its surroundings using a three‐step workflow to obtain: (a) exhumation/burial rates, (b) erosion rates and (c) palaeoreconstructions of source‐to‐sink domains, between the Permian and the Present. Our synthesis of available t‐T modelling results predicts high exhumation rates in the Anti‐Atlas (0.1 km/Myr) during the Early to Middle Jurassic, and in the High Atlas (0.1 km/Myr) and Rif (up to 0.5 km/Myr) during the Neogene. These rates are comparable to values typical of rift flank, domal or structural uplifts settings. During the other investigated periods, exhumation rates in the Meseta, High‐Atlas, Anti‐Atlas and Reguibat shield are around 0.04 ± 0.02 km/Myr. Interpolation of the exhumation rates at the regional scale allow calculation of the volume of rocks eroded. Estimates of erosion rates are between 0.2 x 10³ and 7.5 x 10³ km³ (in the Meseta and the Reguibat Shield respectively). Ten erosional (quantitative, from interpolation results) and depositional (qualitative, from data synthesis) “source‐and‐sink” maps have been constructed, with emphasis on the Jurassic and Cretaceous periods. The maps integrate the extent of exhumed domains, using information from geological maps, lithofacies and biostratigraphic data from new geological fieldwork and well data from onshore and offshore basins. The results illustrate changes in the source‐to‐sink systems and allow for a better understanding of the Central Atlantic margin hinterlands evolution.

In this study we integrate data from over thirty published LTT and t‐T modelling studies from Morocco and its surroundings using a 3‐step workflow to obtain 1) exhumation/burial rates, 2) erosion rates, and 3) paleoreconstructions of source‐to‐sink domains (Source‐and‐Sink maps), between the Permian and the Present.